Low-profile power-generating wind turbine

ABSTRACT

A wind turbine is disclosed which uses energy in air moving relatively toward the turbine to focus and increase the velocity of air entering a turbine inlet air flow passage. The inlet flow passage discharges focused and accelerated air to blades of a rotor where the blades interact with that air to turn the rotor. Rotor motion can be used to operate an electrical generator. The plane of rotation of the rotor can be at substantially right angles to the plane of the passage inlet opening. Baffles in the flow passage and stator vanes adjacent the rotor blades cause the mass flow of the accelerated air to be substantially uniform, and desirably directed, throughout the rotor&#39;s blade area. The turbine is compact and operates quietly.

CROSS-REFERENCE TO REFERENCE TO RELATED APPLICATION

This application is a continuation of pending U.S. patent applicationSer. No. 13/009,735, filed Jan. 19, 2011, entitled LOW-PROFILEPOWER-GENERATING WIND TURBINE, which claims priority to and the benefitof U.S. Provisional Application No. 61/296,280, filed Jan. 19, 2010, theentire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

This invention pertains to wind turbines which have low profiles, whichare quiet when operating, and which can be used for generatingelectrical power. More particularly, the invention pertains to such windturbines which collect ambient wind air and concentrate and direct thatair to and through a radially-bladed rotor at a throat of a turbine airinlet passage.

BACKGROUND

It is known to generate electrical power by use of wind-poweredmechanisms. Known mechanisms for such purposes generally are of twokinds, namely, wind turbines which commonly have rotors resemblingaircraft propellers which rotate about horizontal axes, and verticalaxis wind turbines which commonly have long vertically extending bladesas components of a cylindrical rotor. The rotors of those two kinds ofwind turbines are connected to rotatable shafts which are suitablyconnected to generators which output electrical power. The generatorscommonly produce DC power which commonly is converted to AC power of adesired frequency, such as by use of inverters.

Both of those kinds of wind turbines, with possible rare exception, havefixed locations. Also, both of those kinds of wind turbines haveconsiderable height. The generators of horizontal axis wind turbines areenclosed in housings (commonly called “nacelles”) located atop towers ofsufficient height to provide suitable clearance between the ground andthe ends of the rotor blades which extend radially in a common verticalplane from a central hub on the horizontal rotational axis of the rotor.Horizontal axis wind turbines having overall heights well in excess of120 meters are in use.

Such horizontal and vertical axis turbines share a common attribute,namely, their rotors are exposed to, and perform in direct response to,ambient wind conditions. For that reason, local winds must have speedsgreater than a characteristic minimum speed before the turbines rotatesufficiently rapidly, or with sufficient power (torque), to produceuseful generator output.

The requirement of such known wind turbines that they have fixedlocations is a disadvantageous limitation of them. Also, theirconsiderable-to-large height limits the places where they can be usedsafely or without objection to their appearance.

SUMMARY

This invention provides a wind-driven power generation turbine whichdiffers significantly in concept and structural arrangement from thehorizontal axis and vertical axis wind turbines reviewed above. Turbinesaccording to this invention can be of small height and can be portable.Their small height enables them to be used on buildings in urban areas,e.g.; when portable, they can be used for such times as are needed indifferent locations, such as in support of construction activities or insupport of military operations, as examples of utility. The present windturbines are quiet in operation and are easily accessible formaintenance. They can be provided in a wide range of sizes and powergeneration capabilities.

Generally speaking in terms of structure, this invention provides a windturbine having an ambient air flow inlet passage which extends betweeninlet and outlet ends. Between those ends, the passage has a selectedeffective length and configuration. The inlet end has an inlet openingof relatively large area compared to a passage outlet opening at thepassage's outlet end. Between its ends, the passage configurationincludes a decrease in the passage cross-sectioned area. A rotor islocated proximate to the passage outlet opening. The rotor is rotatableabout an axis which is substantially aligned with a rear portion of thelength of the passage which terminates at the outlet opening. The rotorincludes an array of radially extending blades which are spacedregularly about the rotor axis. The blades can interact with air movingthrough the passage outlet opening to produce rotation of the rotorabout its axis.

Generally speaking in terms of procedure, this invention provides amethod for generating electrical power from wind energy. The methodincludes providing an electrical generator, a rotor and an air flowpassage. The rotor carries an array of blades defined to interact withair moving past them to produce rotation of the rotor. The air flowpassage has a relatively large effective inlet opening area and arelatively small outlet opening area. The inlet and outlet openings arespaced along the passage which decreases in cross-sectional area betweenthose openings. The method includes positioning the rotor sufficientlyclose to the passage outlet opening that air moving through the outletopening can effectively interact with the rotor blades to producerotation of the rotor. Another procedural step of the method is couplingthe generator to the rotor so that the generator operates to generateelectrical energy in response to rotation of the rotor. Another step ofthe method is orienting the passage so that the inlet opening faces intothe direction from which ambient air moves relatively toward the inletopening.

As air moves relatively toward the passage inlet opening, the air entersinto the inlet passage and moves along the passage to the outlet openingand the rotor. The decreasing cross-sectional area of the passage causesthe velocity of the air in the passage to increase as it moves along thepassage. As a result, the air interacting with the rotor blades is moreenergetic per unit of volume than the air which enters the passage. Theincreased velocity of the air interacting with the rotor blades issignificant because the power available in moving air (wind) isproportioned to the cube of the air velocity.

DESCRIPTION OF THE DRAWINGS

The design principles, some presently preferred structural arrangementsof turbines according to this invention, and the procedural affects ofthe invention are depicted in the drawings which accompany andillustrate the description which follows. Those illustrations arecomprised by figures as follows:

FIG. 1 is a drawing presenting a simplified schematic depiction of aturbine the invention to illustrate certain principles of the invention;

FIG. 2 is a drawing which shows a top view of the turbine rotor;

FIG. 3 is a drawing showing a longitudinal cross-sectional elevationview of a turbine of the invention supported on a wheeled foundation;

FIG. 4 is an elevation view of the inlet (front) end of the turbineshown in FIG. 3 as taken along line 4-4 in FIG. 3;

FIG. 5 is an enlarged fragmentary cross-section view of the stator vanesand rotor blades in a turbine of the invention;

FIG. 6 is an elevation view, partially in cross-section, which shows howa turbine of the invention can be located on a building having a pitchedroof;

FIG. 7 is an exploded perspective view showing how the turbine air inletpassage and a stator vane array can be defined;

FIG. 8 is a drawing showing how a turbine according to the invention,located at a fixed location, can be adjusted in position to face intothe direction of an ambient wind; and

FIG. 9 is a fragmentary perspective view of structure which can be anarea to movably support a turbine in a suspended state in a case wherethe foundation for the turbine is located above the turbine.

DETAILED DESCRIPTION

FIG. 1 is presented to illustrate principles of the operation andstructure of a wind turbine according to this invention. FIG. 1 shows alow-profile power-generating wind turbine 10 in simplified and somewhatidealized form. The turbine includes a round rotor 11 which carriesaround its circumference a plurality of regularly spaced radiallyextending blades 12 of desired length and shape. The rotor is positionedfor rotation in a plane which is substantially parallel to an outlet end15 an inlet air flow passage 13 which has an inlet end 14 spaced in anupstream direction along the inlet passage from the rotor. An optionaloutlet air flow passage 16 can have an outlet end 17 spaced in adownstream direction from the rotor.

The portion 18 of the inlet passage 13 closely adjacent the rotor on itsupstream side preferably is straight, of substantially constantdiameter, and aligned with the rotor axis of rotation; that portion ofthe passage defines a passage throat. Passage 13 between inlets 14 andthroat 18 is defined to decrease, preferably substantially smoothly incross-sectional area proceeding from the inlet to the throat. Duringtimes of its operation to generate electrical power, the turbine isoriented so that the opening at inlet end 14 of passage 13 faces intothe direction from which air (actual or relative wind) moves toward theturbine. The rearwardly tapering shape of the air inlet passagecooperates with air entering the inlet and moving along the passage tocause that air to increase in velocity as the air moves along thepassage. As a result, the air in passage 13 at the upstream side ofrotor 11 is more energetic per unit volume of air than is the air justmoving into the passage inlet. Therefore, the air entering the spacesbetween the rotor blades moves faster and can act more forcefully on therotor blades than can a comparable volume of the air just moving intothe passage inlet.

The focused and accelerated nature of the air which acts on the rotor ofa wind turbine according to this invention distinguishes such a turbinefrom wind turbines of the kinds reviewed above in which wind merelyblows on the turbine rotor and does not undergo significant velocityincreasing and focusing processes before interacting with the turbinerotor.

After passage through rotor 11, air flowing through turbine 10 eitherexits from the turbine or enters outlet passage 16 which, if present,extends between rotor 11 and outlet 17. An air outlet passage 16 canincrease in cross-sectioned area from the area of throat 86 to the areaof the outlet opening of outlet passage which can have substantially thesame area as the inlet opening to the turbine. Air outlet passage 16 canenable air in it to expand and reduce velocity progressively so that thevelocity and pressure of air leaving the turbine is substantially equalto the pressure and velocity of air entering the turbine. However, ithas been found that a turbine according to this invention which does notinclude an air outlet passage is effective and may be preferred,especially where low overall height is a desired property of theturbine.

The foregoing description of inlet air flow passage 13 and of itsdifferent portions, apart from mention of rotor 11, is consistent withthe description of a straight venturi tube. It is within the scope ofthis invention that passage 13 can be straight along its length.However, to make turbine 10 more compact end-to-end, and for otherreasons discussed or made apparent later herein, it is preferred, whenimplementing the principles of the invention, to form passage 13 so thatits throat 18 is substantially vertical relative to a substantiallyhorizontal portion of the passage adjacent inlet end 14. FIG. 1 showssuch a passage configuration, referred to here as a “right turn passage”or RTP. It is envisioned that the bend in an inlet air passage in aturbine of the invention can be greater than a 90E bend.

If a turbine inlet air flow passage is straight to and through therotor, the velocity and mass flow rate of air passing through the rotornormally will be substantially uniform at different locations around theperiphery of the rotor where the rotor blades are located. That is adesirable condition. On the other hand, if there is a bend in theturbine inlet air flow passage upstream of the rotor, the fact that airhas mass can cause the mass distribution of air at the rotor to benon-uniform; a larger share of the mass of the air at the rotor likelywill be found in that part of the passage throat which corresponds tothe outside of the passage bend. To counteract and control suchunbalancing of air distribution in a turbine having a right turn passageas shown in FIG. 1, turbine 10 preferably includes a primary partitionor baffle 20 extending in the passage from just forwardly of the rotorblades toward the passage inlet. Partition 20 preferably is positionedand contoured, in cooperation with the contours of the passage inletportion so that substantially equal fractions of the overall quantity ofair entering inlet 14 flow to the forward and rear halves of the annulararea of the rotor in which the rotor blades 12 are located; see FIG. 2and remarks which follow. The positioning and contouring of the primarypartition between its front extent and its rear end adjacent the rotorpreferably is defined so that each half of passage 13 (the half leadingto the front of the rotor and the half leading to the rear of the rotor)have substantially equal effects to increase the velocity of the airmoving from inlet 14 to the rotor location.

As shown in FIG. 1, primary partition 20 preferably is generallyhorizontally disposed in passage 13 at its upstream end. The air movingin the passage above partition 20 constitutes an upper air stream whichis directed to the forward portion of rotor 11, and the air moving inthe passage below partition 20 constitutes a lower air stream which isdirected to the rear portion of the rotor. Each of the upper and lowerair streams can be, and preferably are, substantially equally subdividedby one or more secondary partitions 21 composed of upper-forwardsecondary partitions 21′ and of lower-rear secondary partitions 21″. Aswith the primary partition 20, the arrangement of the secondarypartitions is defined within passage 13 so that the air in eachsubdivision of the upper and lower air streams moving toward rotor 12undergoes substantially equal velocity increasing effects. As a result,all the rotor blades 12 encounter substantially the same conditions ofair velocity and mass distribution. The number of secondary partitions21 provided in a turbine 10 can be varied with the size of the turbine;4 or 5 secondary partitions 21′ and 21″ can be appropriate in a turbinehaving a large diameter rotor.

As shown in FIGS. 1 and 5, turbine 13, particularly in the case where ithas a right turn inlet air flow passage, can include a set of regularlyspaced fixed stator vanes 22 immediately in front of the rotor blades12. The stator vanes coact with air moving past them so that thedirection of movement of air leaving the vanes has a desired directionrelative to the shapes of the rotor blades. The effect of the statorvanes is to enable the rotor blades to more efficiently and effectivelyrespond to the forces applied to the rotor blades by the passing air toturn rotor 11 more forcefully in the desired direction of the rotor. Thestator vanes preferably extend radially of the turbine axis and can besupported between inner and outer supportive cylindrical shrouds whichare fixed relative to a foundation or base for the turbine; see FIG. 7.The inner stator vane shroud support can extend inwardly from thatshroud adjacent the rotor; if that shroud support is located below therotor, as where air moves upwardly through the passage throat 16, thatshroud support can provide at least some support for rotation of therotor relative to it about the turbine axis. Also, it will be apparentthat, if desired, the turbine can be a multi-stage turbine in which atleast one further group of stator vanes and rotor blades are locateddownstream adjacent to the first group of vanes and blades encounteredby air as it moves through throat 18.

Rotation of turbine rotor 11 is used to turn the rotor of a generator 24thereby to produce electrical power which can be used directly from thegenerator. If the generator is a DC generator and AC power is desiredfor use, the output of the generator can be applied to an inverter 25.In implementations of this invention which use right turn inlet air flowpassages to enable the turbine rotor to turn about a vertical axis, therotor can be connected to the upper end of a rotatable output shaft 26which can extend downwardly from the rotor. The lower end of shaft 26can be connected directly to the generator. More preferably, however,the turbine output shaft is coupled to the generator through a rightangle drive 27 which can have an effective gear ratio different from(preferably greater than) 1:1. If the rotor shaft and the generatorinput shaft are to be aligned, a planetary gear arrangement can be usedto couple the two shafts.

In addition to the use of bearings which support rotor shaft 26 forrotation in the turbine, it is desirable also to use thrust bearings tosupport the rotor shaft. Thrust bearings which are effective in oppositedirections are desirable since air moving through the rotor can applysufficient force on those blades to move the rotor and its shaft in thedirection of the air flow.

FIG. 2 is a fragmentary plan view of a rotor 11 useful in a turbine 10having a right turn inlet air flow passage through the throat of whichair moves in an upward direction. Broken line 27 is present in FIG. 2 todenote that rotor blades 12 (only three of which are shown) are presentaround the entire periphery of the rotor. Forward and rear directions inthe turbine are indicated. FIG. 2 shows the locations where the upperend of primary passage partition 20 terminates relative to the rotor todefine forward 30 and rear 31 equal-area semicircular arcuate zonesthrough which the rotor blades pass as the rotor turns. FIG. 2 alsoshows the locations relative to zones 30 and 31 of the upper rear endsof secondary partitions 21′ and 21.″ That is, the air which moves alongpassage 13 above partition 20 passes through throat 18 to the statorvanes and rotor blades through ducting discharge openings havingsubstantially the same collective shape as zone 30 shown in FIG. 2.Similarly, the air which moves along passage 13 below partition 20approaches the stator vanes and rotor blades through ducting dischargeopenings having substantially the same collective shape as zone 31 inFIG. 2. Together, those ducting discharge openings form a circle belowthe stator vanes. That circle can form the boundary of a substantiallycircularly cylindrical space inside the turbine around which theinner-front and lower-rear halves of passage inlet portion pass. Rotorshaft 26, generator 24, inverter 25, and related elements of thecoupling of the rotor to the generator can be located in thatcylindrical space. The floor of that space can be mounted on afoundation for the turbine or can be a part of such a foundation. Thatspace can have its own enclosure 33 (see FIG. 8) separate from thestructure defining air flow passage 13.

FIG. 2 also shows that rotor 11 can have a central hub 34 to which theupper end of shaft 26 can be secured in alignment with the rotationalaxis of the rotor.

FIG. 3 shows that the foundation on which the turbine can be supportedcan be a trailer frame 36 (such as a frame similar to a frame for a boattrailer) having an axle and wheels 37. The front end of the trailer isindicated at 38. FIG. 3 also shows that the output of a right angledrive 27 powered by rotor shaft 26 can be coupled to a gearbox 39 by abelt 40.

FIGS. 3 and 4 show that the effective area of the inlet opening to inletair flow passage 13 can be enlarged by auxiliary structures movablymounted to the passage structure around the inlet opening. In FIG. 4,the fixed structure of the passage defines top 42, bottom 43, and side44 edges of the opening. Since turbine 10 is shown in FIG. 3 to becarried on a movable vehicle, it can be useful to close the opening topassage 13 when the vehicle is in motion as well as, perhaps, othertimes when the turbine is not in use. To that end, turbine 10 can beequipped with doors for selective closure of the passage inlet opening.Such doors can be upper and lower doors 45 and 46 which can be hinged tothe top and bottom edges, respectively, of the passage inlet opening.Doors 45 and 46 can extend along the full width of the inlet opening.Doors 45 and 46 can be supplemented by movable (hinged) side panels 47mounted to the side edges 44 of the passage inlet opening; the sidepanels, when disposed substantially in the plane of the outlet opening,extend along the height of the inlet opening but preferably onlypartially across the width of the opening. When the inlet opening is tobe closed, the doors and side panels can be moved to closed positionssubstantially in the plane of the outlet opening with the side panelsoverlapped by the doors.

During times when it is desired to operate the turbine, the doors andpanels can be opened and moved to defined air capture positions in whichthey are disposed at angles to the plane of the passage inlet opening.In FIG. 3, doors 45 and 46 are shown to have been moved about 135E fromtheir closed positions, and the side panels can have been moved throughsimilar angles;

the doors and side panels are suitably held in their open positions.FIG. 4 shows that the spaces between adjacent edges of the opened doorsand side panels can be closed by gusset elements 48. The gussets can bedefined by suitably shaped (such as triangular) pieces of canvas, e.g.,and can be secured, as by grommets and pins, to the adjacent edges ofthe doors and side panels. The arrangement of open doors and sidepanels, and installed gussets, around the fixed boundaries of thepassage inlet opening significantly increases the effective area of thepassage inlet opening.

FIGS. 3 and 4 depict the use of doors 45 and 46 which each closeone-half the area bounded by the opening top, bottom and side edges45-47. If desired, doors dimensioned at the full height of that openingcan be provided; such full-height doors can be disposed in overlyingrelation to each other when they are closed.

FIG. 5 depicts a workable relation between rotor blades 12 and statorvanes 22. Preferably, as shown, there is a space between the upper edgesof the stator vanes and the adjacent lower edges of the rotor blades.That space is useful to the desired quiet operation of a turbineaccording to the invention.

FIG. 6 shows that a turbine 10′ according to this invention whichincludes a right turn inlet air flow passage can have its passage inlet14 located above its outlet so that air flows downwardly through statorvanes 22 and rotor blades 12. Turbine 10′ can have advantages in useswhere blowing snow, or other particulate matter moving along or close tothe ground, may be encountered. Further, FIG. 6 shows that turbine 10′can be supported atop a building 50 having a pitched roof 51 in whichthe roof surfaces form boundaries of air inlet and air outlet passagesof the turbine.

If a turbine according to this invention is supported on a movablefoundation, such as a trailer as shown in FIG. 3, the turbine canreadily be positioned on the ground so that the inlet 14 of the turbineinlet air flow passage faces directly into an oncoming wind; if the windshifts appreciably in direction, the turbine can be repositioned orreoriented as needed. However, this invention contemplates turbineshaving such large diameter rotors that reorientation of the turbinefoundation is not practical, as well as turbines located atop buildingswhere access to the turbine for reorientation of the turbine is notworkable or realistically possible. In the latter situations, theturbines may be self-orienting on their foundations; an illustration ofa self-orienting turbine 10″ is found in FIG. 8. The air flow passage 13of turbine 10″ and the structure in it can be as described above. Theinlet air flow passage 13 of that turbine can be supported on a base 55which, in turn, can be movably supported, as by rollers 56, on astationary foundation 57 such as a rooftop or the ground. The turbinepreferably is so mounted on the base that the turbine axis (i.e., theaxis of rotation of the turbine rotor) and the axis of rotation of thebase are coincident at 58. As noted above, the rotor drive shaft andrelated power generation equipment can be located in a round housing 33aligned with axis 58 separate from the structure forming air flowpassage 13. The inlet air flow passage structure can be movable aroundhousing 33, and so housing 33 can be supported on foundation 57 and canextend through a central hole in base 55. In some instances, air flowpassage structures of turbine 10″ can be self-orienting since the outletair flow passage structure, if present can function in a manner akin tothe tail of a weathervane; wind forces acting in the outside of theturbine can turn the turbine about axis 58. In other instances, such aswhere the turbine rotor diameter is large, the turbine base 40 can berotated by a suitable base drive mechanism 59 (denoted as a yaw drive),such as a motor driven pinion gear engaged with a ring gear carried bythe base; see FIG. 8. Operation of the base drive mechanism can becontrolled using information obtained from a wind direction sensor 60suitably positioned on or associated with the turbine.

If a self-orienting turbine is large, it can be useful to providemovable support for the portion of the airflow passage structure which,if present, is located above the top of the inlet air flow passagethroat. Such support is shown in FIG. 8 where the outlet portion 16 ofthe turbine air flow passage structure is located above the passagethroat. More specifically, passage outlet portion 19 can be movablysupported, as by a roller 62 connected to the lower exterior of thatpassage portion, on an annular platform 63 disposed perpendicular toaxis 58 and preferably located suitably above foundation 57. Platform 63can be carried on supports 64 which preferably are located in a circularpattern concentric to axis 58. The diameter of the pattern of supports64 is sufficiently large that the turbine can be rotated 360° about axis58 inside the platform supports.

FIG. 7 is an exploded perspective view of structural components usefulto define aspects of an inlet air flow passage of a turbine of thisinvention. The depicted components are a bottom passage subassembly 70,a top passage subassembly 71, and a stator subassembly 72. Subassembly70 defines a circular structural framework 73 having a height whichapproximates the distance between a turbine base plane and its rotorplane. In the upper forward half of the framework 73 is located asemicircular air deflector 74 which forms surfaces of an upper inlet airflow passage and to which the rear extent of principal air flowpartition 20 can be connected at lower deflector edge 75. As illustratedin FIG. 7, the air deflector 74, which defines the upper inlet air flowpassage, includes a semi-annular horizontal wall, a semi-conical wallextending upward and rearward from a rear edge of the semi-annularhorizontal wall, a semi-cylindrical wall extending upward from a rearedge of the semi-conical wall, and a pair of vertical wall segmentsextending radially outward from respective opposite ends of thesemi-cylindrical wall. A lower semicircular air deflector 76 is carriedin the lower half of subassembly 70 at its rear. Deflector 76 can beshaped as one-half of a right circular conic section; it is concaveupwardly. Air moving to deflector 76 passes below deflector 74. Theupper edge of deflector 76 is shown to be at the mid-height of framework73. The forward portion of subassembly 70 can be closed on its sides (asat 77), its bottom (as at 78), and its top (not shown) to define otheraspects of inlet air flow passage 13 rearwardly of its rectangular openinlet end 14.

Subassembly 71 is shown to be comprised principally by a circularstructural ring member 79 and by a semicircular cylindrically curvedskirt 80 which depends from ring member 79 a distance equal to thespacing of the upper edge 81 of lower deflector 76. When ring member 79is properly positioned on and secured to the upper structural ring ofsubassembly 70, skirt 80 connects to deflector 76 at its edge 81 andcloses the upper rear half of framework 73.

Stator assembly 72 includes stator vanes 22 which are carried betweeninner 83 and outer 84 circularly cylindrical vane supporting shrouds.The stator assembly preferably is annular in shape. The stator assemblyis connected to ring member 79 of subassembly 71 as the turbine isassembled.

It was mentioned earlier that a turbine of this invention can be mountedin an inverted position. A form of inverted turbine in which air flowsdownward through the rotor blades is shown in FIG. 6; in that instancethe turbine is not movable about its axis relative to its supportstructure. It is possible to mount in an inverted position a turbinewhich is movable about its rotor axis relative to the turbine'ssupports; FIG. 9 depicts one way in which an angularly movable turbinecan be supported from above.

As shown in FIG. 9, a turbine support ring 90 can be supported below afoundation (not shown) by brackets 91 depending from a bracket base 92.Several brackets and bracket base assemblies can be attached to supportring 90 at spaced location around the ring. Each bracket base can beconnected to the bottom surface of a suitable foundation. The base ofthe inverted turbine can be carried by the support ring via pluraltrolley assemblies 94, one of which is shown in FIG. 9. A trolleyassembly 94 can include a frame 95 which can be suitably secured to theturbine base and to which are rotatably mounted upper 96 and lower 97trolley rollers. The rollers preferably have circumferences contoured tomate closely with the contours of support ring 90. The trolley rollersare located on frame 95 so that the trolley assemblies move along thesupport ring and not vertically or radially relative to the supportring. Angular motion of the related turbine relative to the support ringaxis can be obtained by operation of one or more drive motors connectedto one or more of the upper trolley rollers.

It is envisioned that a right turn passage turbine according to thisinvention having a rotor diameter on the order of 80 feet can have aheight of about 12 feet at its rotor plane.

As noted above, the power available in a wind is proportional to thecube of the wind's velocity, which means that doubling the wind velocityincreases the available power by a factor of eight. A small differencein wind velocity can mean a large difference in available energy and inelectricity produced, and therefore a large difference in the cost ofelectricity produced. It will be seen that the turbines of thisinvention, characterized by comparatively small structures whichmeaningfully increase inlet air velocities, can produce significantquantities of electricity. The low profiles (small heights) of thepresent turbines mean that the turbines can be used in places where highprofile turbines cannot be used or are not acceptable.

Turbines of this invention operate in response to energy in air movingrelatively toward the inlet air openings of the turbines. When theturbine is used at a geographically fixed location, such relative airmovement is due to a wind moving past that location. It will beappreciated that such relative air can be caused by movement of theturbine itself, such as is the case where the turbine is located on avehicle which is moved for reasons other then the creation of a relativewind past the turbine. Examples of such vehicles are trains and trucks.Such vehicles move at moderate to high speeds during significantportions of their useful lives, and so this invention contemplates theuse of turbines of the kinds described above on such vehicles.

For example, a small version of a turbine of this invention can bemounted atop a driver's cab of a truck or a truck tractor to generateelectricity useful in the operation of the vehicle. Electrical powergenerated by the turbine can be applied to operate refrigeration systemsaboard the vehicle, as where the vehicle has cargo space for thetransport of frozen or perishable foods. Also, turbine generatedelectrical energy can be used to charge (or recharge) batteries on thevehicle to operate vehicle electrical systems when the vehicle is not inmotion or is moving at low speed.

The present invention has been described above with reference to certainstructural arrangements embodying the invention and with reference tocertain procedural aspects of the invention. The preceding descriptionis not intended to be, nor should it be read as, a comprehensive catalogof all forms in which the invention can be embodied or procedurallyimplemented. Variations and modifications of the described aspects ofthe invention can be practiced without departing from the fair scope ofthe invention.

What is claimed is:
 1. A wind turbine, comprising: an airflow passageextending between an inlet end defining an inlet opening having a firstarea and an outlet end defining an outlet opening having a second areasmaller than the first area, wherein the inlet end defines an anglerelative to the outlet end; a rotor proximate to the outlet opening, therotor comprising a plurality of blades defining an annular area, whereinthe blades are configured to rotate about a rotor axis substantiallyparallel to an axis of the outlet end of the airflow passage whensubject to airflow moving through the airflow passage; an output shaftcoupled to the rotor to transmit mechanical energy from the rotor to agenerator; and a primary partition extending between the inlet openingand the outlet opening, the primary partition defining an upper passageconfigured to direct airflow to a forward half of the annular area ofthe blades and a lower passage configured to direct airflow to arearward half of the annular area the blades such that the distributionof airflow across the blades is substantially uniform.
 2. The windturbine of claim 1, wherein the angle is substantially 90 degrees. 3.The wind turbine of claim 1, wherein the inlet end of the airflowpassage is substantially horizontal and the outlet end of the airflowpassage is substantially vertical.
 4. The wind turbine of claim 3,wherein a portion of the primary partition proximate to the inletopening is substantially horizontal and a portion of the primarypartition proximate to the outlet opening is substantially vertical. 5.The wind turbine of claim 1, wherein the primary partition comprises: ahorizontal wall; a vertical semi-cylindrical wall coupled to thehorizontal wall; and first and second vertical wall segments extendingradially outward from respective opposite ends of the verticalsemi-cylindrical wall.
 6. The wind turbine of claim 1, furthercomprising a plurality of fixed stator vanes disposed in the airflowpassage upstream of the plurality of blades, wherein the plurality ofstator vanes are configured to direct the airflow in a desired directionrelative to the plurality of blades.
 7. The wind turbine of claim 6,wherein the plurality of stator vanes defines an annular areasubstantially equal to the annular area of the plurality of blades. 8.The wind turbine of claim 1, wherein the airflow passage uniformlytapers between the inlet end and the outlet end.
 9. The wind turbine ofclaim 1, wherein the airflow passage further comprises: a plurality ofupper secondary partitions extending between the inlet opening and theoutlet opening, the upper secondary partitions dividing the upperpassage into a plurality of substantially equal upper airflowsubdivisions; and a plurality of lower secondary partitions extendingbetween the inlet opening and the outlet opening, the lower secondarypartitions dividing the lower passage into a plurality of substantiallyequal lower airflow subdivisions.
 10. The wind turbine of claim 9,wherein each of the plurality of upper secondary partitions issubstantially vertical and each of the plurality of lower secondarypartitions is substantially vertical.
 11. The wind turbine of claim 1,wherein the each of the plurality of blades extends radially outwardrelative to the rotor axis and wherein the plurality of blades extendsaround a perimeter of the rotor.
 12. The wind turbine of claim 1,further comprising: a rotatable base supporting the airflow passage; anda drive motor operatively coupled to the base, wherein actuation of thedrive motor rotates the base to reorient the airflow passage.
 13. Thewind turbine of claim 12, further comprising a wind direction sensorcoupled to the drive motor, wherein the drive motor is configured torotate the base based on input signals received from the wind directionsensor.
 14. A wind turbine according to claim 1, further comprising atleast one door hingedly coupled to the inlet end of the airflow passage,wherein the at least one door is configured to move between a closedposition covering at least a portion of the inlet opening and an openposition in which the door defines an effective inlet area larger thanthe first area of the inlet opening.
 15. The wind turbine of claim 1,further comprising: a base supporting the airflow passage; and aplurality of rollers coupled to the base, wherein the rollers areconfigured to facilitate reorienting the airflow passage.
 16. A windturbine, comprising: a rotor comprising a plurality of blades arrangedin an annular array and configured to rotate about a vertical rotoraxis; an output shaft coupled to the rotor; an upper airflow passagedefining a horizontal inlet and a substantially vertical outlet, whereinthe upper airflow passage is configured to direct an upper airstream toa forward half of the annular array; and a lower airflow passagedefining a horizontal inlet and a substantially vertical outlet, whereinthe lower airflow passage is configured to direct a lower airstream to arearward half of the annular array.
 17. The wind turbine of claim 16,further comprising a primary partition separating the upper airflowpassage from the lower airflow passage.
 18. The wind turbine of claim17, wherein a portion of the primary partition proximate to thehorizontal inlets is substantially horizontal and a portion of theprimary partition proximate to the vertical outlets is substantiallyvertical.
 19. The wind turbine of claim 17, wherein the primarypartition comprises: a horizontal wall; a vertical semi-cylindrical wallcoupled to the horizontal wall; and first and second vertical wallsegments extending radially outward from respective opposite ends of thevertical semi-cylindrical wall.
 20. The wind turbine of claim 17,further comprising: a plurality of upper secondary partitions dividingthe upper airflow passage into a plurality of upper airflowsubdivisions; and a plurality of lower secondary partitions dividing thelower airflow passage into a plurality of lower airflow subdivisions.21. The wind turbine of claim 16, wherein each of the plurality ofblades extends radially outward relative to the vertical rotor axis.